compile err

[ayamada]

I get the following error when I try to compile lftp-3.1.3 .
Could some one please help me !!

My os is
HP-UX B.11.00 A 9000/800 2000165771 two-user license

GCC:
Reading specs from /usr/local/lib/gcc-lib/hppa2.0n-hp-hpux11.00/3.1/specs
Configured with: ./configure  : (reconfigured) ./configure  : (reconfigured) 
/configure
Thread model: posix
gcc version 3.1


make[1]: Entering directory `/d1/lftp-3.1.3/src'
if /bin/sh ../libtool --silent --tag=CXX --mode=compile 
gcc -DHAVE_CONFIG_H -I. -I. -I../include -I../include -I/usr/local/ssl/include 
  -I/usr/local/include  -O2 -Wall -Wwrite-strings -Woverloaded-virtual -fno-exceptions 
 -fno-rtti -fno-implement-inlines -Winline -MT Resolver.lo -MD -MP -MF 
".deps/Resolver.Tpo" -c -o Resolver.lo Resolver.cc; \
then mv -f ".deps/Resolver.Tpo" ".deps/Resolver.Plo"; else rm -f 
".deps/Resolver.Tpo"; exit 1; fi
cc1plus: warning: changing search order for system directory "."
cc1plus: warning:   as it has already been specified as a non-system 
directory
cc1plus: warning: changing search order for system directory 
"/usr/local/include"
cc1plus: warning:   as it has already been specified as a non-system 
directory
Resolver.cc: In function `int extract_domain(const unsigned char*, const
   unsigned char*, int, char*, int)':
Resolver.cc:400: `dn_expand' undeclared (first use this function)
Resolver.cc:400: (Each undeclared identifier is reported only once for each
   function it appears in.)
Resolver.cc:401: `dn_skipname' undeclared (first use this function)
make[1]: *** [Resolver.lo] Error 1
make[1]: Leaving directory `/d1/lftp-3.1.3/src'
make: *** [all-recursive] Error 1